login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

G.f. A(x) satisfies: A(x - A(x)^3) = x + A(x)^2.
1

%I #14 Mar 10 2023 07:41:41

%S 1,1,3,12,57,300,1697,10126,62991,405247,2680901,18160444,125562250,

%T 883868590,6321838520,45869309028,337167193262,2508018933431,

%U 18861358215299,143293615189089,1098997404472941,8504070741463729,66358269984208701,521923129718567918,4136089275165532156,33013640650845937124

%N G.f. A(x) satisfies: A(x - A(x)^3) = x + A(x)^2.

%H Paul D. Hanna, <a href="/A276366/b276366.txt">Table of n, a(n) for n = 1..300</a>

%F G.f. A(x) satisfies: A'(x - A(x)^3) = (1 + 2*A'(x)*A(x)) / (1 - 3*A'(x)*A(x)^2).

%e G.f.: A(x) = x + x^2 + 3*x^3 + 12*x^4 + 57*x^5 + 300*x^6 + 1697*x^7 + 10126*x^8 + 62991*x^9 + 405247*x^10 + 2680901*x^11 + 18160444*x^12 +...

%e such that A(x - A(x)^3) = x + A(x)^2.

%e RELATED SERIES.

%e A(x - A(x)^3) = x + x^2 + 2*x^3 + 7*x^4 + 30*x^5 + 147*x^6 + 786*x^7 + 4480*x^8 + 26814*x^9 + 166865*x^10 + 1072160*x^11 + 7076724*x^12 +...

%e which equals x + A(x)^2.

%o (PARI) {a(n) = my(A=[1], F=x); for(i=1, n, A=concat(A, 0); F=x*Ser(A); A[#A] = -polcoeff(subst(F, x, x-F^3) - F^2, #A) ); A[n]}

%o for(n=1, 30, print1(a(n), ", "))

%Y Cf. A153851, A275765, A276364.

%K nonn

%O 1,3

%A _Paul D. Hanna_, Sep 01 2016